cxl/pmem: Remove the cxl_pmem_wq and related infrastructure

Now that cxl_nvdimm and cxl_pmem_region objects are torn down
sychronously with the removal of either the bridge, or an endpoint, the
cxl_pmem_wq infrastructure can be jettisoned.

Tested-by: Robert Richter <rrichter@amd.com>
Link: https://lore.kernel.org/r/166993042335.1882361.17022872468068436287.stgit@dwillia2-xfh.jf.intel.com
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/drivers/cxl/core/pmem.c b/drivers/cxl/core/pmem.c
index 4d36805..1644647 100644 (file)
--- a/drivers/cxl/core/pmem.c
+++ b/drivers/cxl/core/pmem.c
@@ -99,7 +99,6 @@ static struct cxl_nvdimm_bridge *cxl_nvdimm_bridge_alloc(struct cxl_port *port)
 
        dev = &cxl_nvb->dev;
        cxl_nvb->port = port;
-       cxl_nvb->state = CXL_NVB_NEW;
        device_initialize(dev);
        lockdep_set_class(&dev->mutex, &cxl_nvdimm_bridge_key);
        device_set_pm_not_required(dev);
@@ -117,28 +116,7 @@ err:
 static void unregister_nvb(void *_cxl_nvb)
 {
        struct cxl_nvdimm_bridge *cxl_nvb = _cxl_nvb;
-       bool flush;
 
-       /*
-        * If the bridge was ever activated then there might be in-flight state
-        * work to flush. Once the state has been changed to 'dead' then no new
-        * work can be queued by user-triggered bind.
-        */
-       device_lock(&cxl_nvb->dev);
-       flush = cxl_nvb->state != CXL_NVB_NEW;
-       cxl_nvb->state = CXL_NVB_DEAD;
-       device_unlock(&cxl_nvb->dev);
-
-       /*
-        * Even though the device core will trigger device_release_driver()
-        * before the unregister, it does not know about the fact that
-        * cxl_nvdimm_bridge_driver defers ->remove() work. So, do the driver
-        * release not and flush it before tearing down the nvdimm device
-        * hierarchy.
-        */
-       device_release_driver(&cxl_nvb->dev);
-       if (flush)
-               flush_work(&cxl_nvb->state_work);
        device_unregister(&cxl_nvb->dev);
 }
 

diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index fc6083b..f0ca2d7 100644 (file)
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -400,34 +400,17 @@ struct cxl_region {
        struct cxl_region_params params;
 };
 
-/**
- * enum cxl_nvdimm_brige_state - state machine for managing bus rescans
- * @CXL_NVB_NEW: Set at bridge create and after cxl_pmem_wq is destroyed
- * @CXL_NVB_DEAD: Set at brige unregistration to preclude async probing
- * @CXL_NVB_ONLINE: Target state after successful ->probe()
- * @CXL_NVB_OFFLINE: Target state after ->remove() or failed ->probe()
- */
-enum cxl_nvdimm_brige_state {
-       CXL_NVB_NEW,
-       CXL_NVB_DEAD,
-       CXL_NVB_ONLINE,
-       CXL_NVB_OFFLINE,
-};
-
 struct cxl_nvdimm_bridge {
        int id;
        struct device dev;
        struct cxl_port *port;
        struct nvdimm_bus *nvdimm_bus;
        struct nvdimm_bus_descriptor nd_desc;
-       struct work_struct state_work;
-       enum cxl_nvdimm_brige_state state;
 };
 
 struct cxl_nvdimm {
        struct device dev;
        struct cxl_memdev *cxlmd;
-       struct cxl_nvdimm_bridge *bridge;
 };
 
 struct cxl_pmem_region_mapping {

diff --git a/drivers/cxl/pmem.c b/drivers/cxl/pmem.c
index 76cf54e..0910367 100644 (file)
--- a/drivers/cxl/pmem.c
+++ b/drivers/cxl/pmem.c
@@ -11,13 +11,6 @@
 #include "cxlmem.h"
 #include "cxl.h"
 
-/*
- * Ordered workqueue for cxl nvdimm device arrival and departure
- * to coordinate bus rescans when a bridge arrives and trigger remove
- * operations when the bridge is removed.
- */
-static struct workqueue_struct *cxl_pmem_wq;
-
 static __read_mostly DECLARE_BITMAP(exclusive_cmds, CXL_MEM_COMMAND_ID_MAX);
 
 static void clear_exclusive(void *cxlds)
@@ -191,105 +184,6 @@ static void unregister_nvdimm_bus(void *_cxl_nvb)
        nvdimm_bus_unregister(nvdimm_bus);
 }
 
-static bool online_nvdimm_bus(struct cxl_nvdimm_bridge *cxl_nvb)
-{
-       if (cxl_nvb->nvdimm_bus)
-               return true;
-       cxl_nvb->nvdimm_bus =
-               nvdimm_bus_register(&cxl_nvb->dev, &cxl_nvb->nd_desc);
-       return cxl_nvb->nvdimm_bus != NULL;
-}
-
-static int cxl_nvdimm_release_driver(struct device *dev, void *cxl_nvb)
-{
-       struct cxl_nvdimm *cxl_nvd;
-
-       if (!is_cxl_nvdimm(dev))
-               return 0;
-
-       cxl_nvd = to_cxl_nvdimm(dev);
-       if (cxl_nvd->bridge != cxl_nvb)
-               return 0;
-
-       device_release_driver(dev);
-       return 0;
-}
-
-static void offline_nvdimm_bus(struct cxl_nvdimm_bridge *cxl_nvb,
-                              struct nvdimm_bus *nvdimm_bus)
-{
-       if (!nvdimm_bus)
-               return;
-
-       /*
-        * Set the state of cxl_nvdimm devices to unbound / idle before
-        * nvdimm_bus_unregister() rips the nvdimm objects out from
-        * underneath them.
-        */
-       bus_for_each_dev(&cxl_bus_type, NULL, cxl_nvb,
-                        cxl_nvdimm_release_driver);
-       nvdimm_bus_unregister(nvdimm_bus);
-}
-
-static void cxl_nvb_update_state(struct work_struct *work)
-{
-       struct cxl_nvdimm_bridge *cxl_nvb =
-               container_of(work, typeof(*cxl_nvb), state_work);
-       struct nvdimm_bus *victim_bus = NULL;
-       bool release = false, rescan = false;
-
-       device_lock(&cxl_nvb->dev);
-       switch (cxl_nvb->state) {
-       case CXL_NVB_ONLINE:
-               if (!online_nvdimm_bus(cxl_nvb)) {
-                       dev_err(&cxl_nvb->dev,
-                               "failed to establish nvdimm bus\n");
-                       release = true;
-               } else
-                       rescan = true;
-               break;
-       case CXL_NVB_OFFLINE:
-       case CXL_NVB_DEAD:
-               victim_bus = cxl_nvb->nvdimm_bus;
-               cxl_nvb->nvdimm_bus = NULL;
-               break;
-       default:
-               break;
-       }
-       device_unlock(&cxl_nvb->dev);
-
-       if (release)
-               device_release_driver(&cxl_nvb->dev);
-       if (rescan) {
-               int rc = bus_rescan_devices(&cxl_bus_type);
-
-               dev_dbg(&cxl_nvb->dev, "rescan: %d\n", rc);
-       }
-       offline_nvdimm_bus(cxl_nvb, victim_bus);
-
-       put_device(&cxl_nvb->dev);
-}
-
-static void cxl_nvdimm_bridge_state_work(struct cxl_nvdimm_bridge *cxl_nvb)
-{
-       /*
-        * Take a reference that the workqueue will drop if new work
-        * gets queued.
-        */
-       get_device(&cxl_nvb->dev);
-       if (!queue_work(cxl_pmem_wq, &cxl_nvb->state_work))
-               put_device(&cxl_nvb->dev);
-}
-
-static void cxl_nvdimm_bridge_remove(struct device *dev)
-{
-       struct cxl_nvdimm_bridge *cxl_nvb = to_cxl_nvdimm_bridge(dev);
-
-       if (cxl_nvb->state == CXL_NVB_ONLINE)
-               cxl_nvb->state = CXL_NVB_OFFLINE;
-       cxl_nvdimm_bridge_state_work(cxl_nvb);
-}
-
 static int cxl_nvdimm_bridge_probe(struct device *dev)
 {
        struct cxl_nvdimm_bridge *cxl_nvb = to_cxl_nvdimm_bridge(dev);
@@ -306,15 +200,12 @@ static int cxl_nvdimm_bridge_probe(struct device *dev)
        if (!cxl_nvb->nvdimm_bus)
                return -ENOMEM;
 
-       INIT_WORK(&cxl_nvb->state_work, cxl_nvb_update_state);
-
        return devm_add_action_or_reset(dev, unregister_nvdimm_bus, cxl_nvb);
 }
 
 static struct cxl_driver cxl_nvdimm_bridge_driver = {
        .name = "cxl_nvdimm_bridge",
        .probe = cxl_nvdimm_bridge_probe,
-       .remove = cxl_nvdimm_bridge_remove,
        .id = CXL_DEVICE_NVDIMM_BRIDGE,
        .drv = {
                .suppress_bind_attrs = true,
@@ -453,31 +344,6 @@ static struct cxl_driver cxl_pmem_region_driver = {
        },
 };
 
-/*
- * Return all bridges to the CXL_NVB_NEW state to invalidate any
- * ->state_work referring to the now destroyed cxl_pmem_wq.
- */
-static int cxl_nvdimm_bridge_reset(struct device *dev, void *data)
-{
-       struct cxl_nvdimm_bridge *cxl_nvb;
-
-       if (!is_cxl_nvdimm_bridge(dev))
-               return 0;
-
-       cxl_nvb = to_cxl_nvdimm_bridge(dev);
-       device_lock(dev);
-       cxl_nvb->state = CXL_NVB_NEW;
-       device_unlock(dev);
-
-       return 0;
-}
-
-static void destroy_cxl_pmem_wq(void)
-{
-       destroy_workqueue(cxl_pmem_wq);
-       bus_for_each_dev(&cxl_bus_type, NULL, NULL, cxl_nvdimm_bridge_reset);
-}
-
 static __init int cxl_pmem_init(void)
 {
        int rc;
@@ -485,13 +351,9 @@ static __init int cxl_pmem_init(void)
        set_bit(CXL_MEM_COMMAND_ID_SET_SHUTDOWN_STATE, exclusive_cmds);
        set_bit(CXL_MEM_COMMAND_ID_SET_LSA, exclusive_cmds);
 
-       cxl_pmem_wq = alloc_ordered_workqueue("cxl_pmem", 0);
-       if (!cxl_pmem_wq)
-               return -ENXIO;
-
        rc = cxl_driver_register(&cxl_nvdimm_bridge_driver);
        if (rc)
-               goto err_bridge;
+               return rc;
 
        rc = cxl_driver_register(&cxl_nvdimm_driver);
        if (rc)
@@ -507,8 +369,6 @@ err_region:
        cxl_driver_unregister(&cxl_nvdimm_driver);
 err_nvdimm:
        cxl_driver_unregister(&cxl_nvdimm_bridge_driver);
-err_bridge:
-       destroy_cxl_pmem_wq();
        return rc;
 }
 
@@ -517,7 +377,6 @@ static __exit void cxl_pmem_exit(void)
        cxl_driver_unregister(&cxl_pmem_region_driver);
        cxl_driver_unregister(&cxl_nvdimm_driver);
        cxl_driver_unregister(&cxl_nvdimm_bridge_driver);
-       destroy_cxl_pmem_wq();
 }
 
 MODULE_LICENSE("GPL v2");